Combustion can support



Jan. 7, 1964 F. G. DOUGHERTY ETAL 3,116,696v

COMBUSTION CAN SUPPORT Filed July 21, 1958 United States Patent3,116,606 COMBUSTION CAN SUPPORT Floyd G. Dougherty, Speedway, Ind., andJohn M. Richey, Cincinnati, Ohio, assignors to General MotorsCorporation, Detroit, Mich., a corporation of Delaware Filed July 21,1958, Ser. No. 749,764 2 Claims. (Cl. 60--39.82)

This invention relates to a combustion can for a gas turbine engine.

More specifically, this invention relates to means for radiallysupporting and axially locating a combustion can with respect to theengine outer casing prior to the insertion therein of a fuel nozzle. Inmany gas turbine engines having a cannular combustion section, the cansare usually supported at the forward end by the fuel nozzle extendingthrough the central aperture in the dome of the can with the rearsection being suitably supported by strut means and other suitablefixtures connected to the engine casing. However, prior to the insertionof the nozzle in the can, no means is provided for maintaining the canin axial alignment or in radial position ready to receive the fuelnozzle. In order to maintain said cans ready for insertion of the fuelnozzle, this necessarily requires much stronger supporting means to therear of the cans, which involves the use of more material rendering thecan heavier, and resulting in a higher cost.

This invention is directed to a can supporting and locating means forsupporting the forward end of the combustion can, as previouslymentioned, prior to the insertion of the fuel nozzle, such aconstruction eliminating the usual supports at the rear of the can andthereby rendering the can lighter and cheaper to manufacture. With theelimination of the heavy supports at the rear of the can, expansion cantake place at this point rather than at the front or dome section of thecan.

This invention consists of supporting the can upon the igniter plug bysecuring a ferrule to the forward end of the can to slidably receive theigniter plug therein, the plug having a locking lug on a portion belowthe ferrule to permit the ferrule to rest on the locking lug and supportthe can from the plug. The ferrule is tapered at one end and providedwith a slot, with the locking lug having a shape such that rotation ofthe locking lug and plug to one position permits the withdrawal of theplug through the ferrule, while rotation of the lug to another positionpermits the ferrule to rest on the lug and support the can from theplug. The plug is then bolted to the engine casing.

Therefore, it is an object of this invention to provide a radiallysupporting and axial locating means for a combustion can to properlyalign and support the can preparatory to the insertion of the fuelnozzle therein.

Other features, advantages and objects will become apparent by referenceto the detailed description of the invention and to the drawings showingthe preferred embodiment of this invention, wherein:

FIGURE 1 is a cross-sectioned view of a portion of the combustionchamber of a gas turbine engine,

FIGURE 1a is an exploded perspective view of a detail,

FIGURE 2 is a bottom view of the igniter plug showing the locking l-ugand plug in one position of rotation, obtained by passing a planethrough the plug and can as indicated by the lines 22 of FIGURE 1, and

FIGURE 3 is a view similar to FIGURE 2 but showing the locking lug andplug in a different position of rotation.

Referring now to the drawings and more particularly to FIGURE 1, thereis shown therein a portion of the combustion section of a gas turbineengine, the outer con fines of the combustion section being defined bythe annular outer engine case 12 connected by suitable flanges and boltassemblies 14 and 16 to the outer engine case ice 2 portions 18 and 2tdefining respectively the diverging diffuser section and the forwardpart of the turbine case.

Suitably annularly positioned within the combustion section it are anumber of combustion cans 22 circumferentially spaced from each other.While only one can 22. is shown, six or more cans are usually providedtherein, said cans being interconnected by conventional crossover tubes(not shown) positioned Within openings 23 for the propagation of theflame therebetween to ignite the fuel in the cans not provided withigniter plugs. As shown, each of the combustion cans '22 is generallycylindrical, having a plurality of ring-like sections 24 joined togetherby annular spacer members 26 corrugated (not shown) to provide thenecessary flow of cooling air therebetween to cool the sheet metal can.

At its rearward portion 25, the can is provided with suitable annularsleeve-like means 27 for slidably receiving the forward portion 29" ofthe transition section (not shown), this portion of the transitionsection being supported at 31 by the outer engine case 29. Such aconstnuction thus supports the rearward portion of the can 22 whilepermitting extension or retraction of the same under thermal expansionor contraction of the can and transition section.

At its forward end, the can is provided with a dome shaped end 28suitably perforated as shown in the conventional manner for cooperationwith a set of swirler blade members 3% provided for inducing vorticityin the incoming air. As seen, suitable primary air inlets 34 and airdilution openings as are provided. The dome end 28 of the can issuitably apertured centrally at 38 for receiving one end ll) of aconventional fuel nozzle 42' having its other end 44 suitably secured tothe diffuser section engine casing 18 as shown. As shown, the fuelnozzle end 40 thus supports the forward end of the combustion can duringnormal operation of the engine.

The means for radially supporting and axially locating the combustioncan with respect to the casing prior to insertion of the fuel nozzle inthe opening in the dome will now be described. In previousinstallations, prior to the insertion of the nozzle in the combustioncan dome 2 8, the combustion can would be cantilevered upon the rearsupport and fall down against the inner engine support, thereby possiblymisaligning all of the cans and making it rather difficult and tediousto align each of the cans with respect to the separate nozzles. Thisinvention eliminates this by providing a construction to be nowdescribed. Formed integrally therewith and projecting forwardly from thefront end of each can 22 at its radial outermost portion 46 is a sheetmetal plate-like portion 48 having a ferrule or hollow boss 50 weldedthereto within an aperture provided in the plate. The ferrule 50 has aconvergent taper 52 at its lower inside diameter, as seen in FIGURE 1,the tapered portion being slotted transversely of the longitudinal axisof the boss at 54 through the entire diameter of the boss.

An igniter plug 56 having the shape shown projects through an opening 58in the outer engine case 12 and through an aperture 6% in the combustioncan dome for igniting the fuel air mixture therein. While only one plugis shown, two or more may be provided for igniting the fuel in the cans,with the crossover tubes (not shown) propagating the flame to the othercans. In this case, the igniter plug is slidably received within theboss or ferrule 50 and is provided on its lower portion 62. between theferrule and opening 64 wvith a lug or locking means 64 comprisingsupport means for supporting the combustion can from the igniter plug.

By referring to FIGS. 1a, 2 and 3, it will be seen that the annular-likelocking lug 6 4 is secured to and surrounds the igniter plug 56 and isprovided on two sides with parallel flats 66, the distance or widthbetween the flats 66 being slightly smaller than the widtn of the slot54 in taper 52 of boss 50. At substantially right angles to sideportions 66, the locking lug is formed with arcuate sections of equalradii having arcuate edges 68, the diameter of said arcuate sectionstogether being slightly less than the inside diameter of the unslotteduntapered portion 53 of the boss 50, while being a larger diameter orwidth than the width of the slot 54. Suitably secured to the upperportion of the igniter plug 56 is a mounting plate 70 provided withsuitable openings 72 for cooperation with similarly spaced openings 74in a plate 76 fixed to the engine outer case 12. Suitable bolts 78 areprovided for connecting the plate 70 to plate 7 6 to support the igniterplug thereon and fix it against rotation.

The method of assembly for supporting the combustion can in thecombustion section 10 will be seen clearly by referring to FIGURES 2 and3. The can 22 is placed within the combustion section 10 with the rearportion 25 engaged with the forward portion 29 of the transitionsection. Prior to insertion of the fuel nozzle 42 in the dome opening 38of the can, the igniter plug 56 is rotated to the position shown inFIGURE 3 to align the two flats 66 of the locking lug with the slot 54.The igniter plug 56 may then be inserted through the opening 53 in theouter engine case 12, through the tapered opening in the boss 50 andinto the opening 60 in the dome. Rotation of the igniter plug assembly90 to the position shown in FIGURE 2 will then position the arcuateedges 68 of the locking lug in alignment with the unslotted portion 55of the tapered end of the boss 50 so that the boss and therefore thecombustion can may rest upon the locking lug to be supported therebypreparatory to insertion of the fuel nozzle in the combustion can dome.With the plug assembly rotated to the FIGURE 2 position, the openings inthe plate 70 are aligned with the openings in plate 76 and casing 12,and the bolts 78 may then be inserted therein and secured to the enginecase to secure the plug assembly and locking lug in its operativeposition. The combustion can is thus radially supported ready forconnection with the fuel nozzle, and is axially located with referenceto the diffuser and transition sections. Any future axial thermalexpansion will then be taken up by the rearward portion 25 of thecombustion can.

Insertion of the fuel nozzle 42 into the aperture 33 of the can willthen raise the can by a slight amount, for example, V inch, thus raisingthe boss 50 out of contact with the lug 64. The boss 50 is thus mountedfor a limited radial movement on the plug by the tapered portion 52being confined between the locking lug 64 on one side, and the shoulderon the enlarged portion of the plug on the other side. In the event thatthe fuel nozzle should become dislodged for some unknown reason, theboss 50 would then again rest upon the lug 64 preventing free movementof the can.

From the foregoing it will be seen that this invention provides alight-weight and effective means of supporting the forward section of acombustion can prior to the insertion therein of the fuel nozzle, thesupport preventing the cans from falling out of position. With thisconstruction, the normally heavy holding structure supporting the rearend of the cans is eliminated resulting in a simpler and cheaperstructure.

As indicated previously, two or more igniter plugs are usually used toignite the fuel in the cans, with the cans being interconnected bycrossover tubes for propagating the flame to the other cans. Since thecans are of the same construction, dummy igniter plugs are placed in theigniter plug openings in the cans not equipped with live igniter plugs.These dummy plugs are of the same size and shape as the live plugs butdo not have electrodes or any electrical connection thereto. It will beseen therefore, that each of the dummy plugs will also be provided witha locking lug for cooperation with the combustion can boss to radiallysupport and axially align the can in the same manner as described inconnection with the cans having live igniter plugs.

While the drawings and specification illustrate and describe thepreferred embodiment of this invention, it will be obvious to thoseskilled in the art that many modifications can be made without departingfrom the scope of the invention.

We claim:

1. In combination in a turbomachine, a casing defining a combustionchamber, a combustion can in said chamber for the burning of fueltherein, said casing and can each having an opening therein forreceiving therethrough opposite ends of a fuel igniter plug, a fueligniter plug insertable through said openings and rotatable to aplurality of positions, means removably securing one end of said plug tosaid casing, and other means slidably mounting said can on said plug fora limited movement with respect to said plug, said other means includingferrule means secured to said can receiving said igniter plugtherethrough in the assembled positions of said plug and can, saidferrule means having portions of different internal diameters, said plughaving a plurality of spaced portions thereon of greater diameter thanthe diameter of one of said ferrule means portions, said plug portionsoverlapping said one of said ferrule means portions in one rotativeposition of said plug confining said ferrule means for a limited slidingmovement between said plug portions.

2. In combination in a turbomachine, a casing defining a combustionchamber, a combustion can in said chamber for the burning of fueltherein, said casing and can each having an opening therein forreceiving therethrough opposite ends of a fuel igniter plug, a fueligniter plug insertable through said openings and rotatable to aplurality of positions, means removably securing one end of said plug tosaid casing, and other means slidably mounting said can on said plug fora limited movement with respect to said plug, said other means includingferrule means secured to said can receiving said igniter plugtherethrough in the assembled positions of said plug and can, saidferrule means having circumferential portions of different internaldiameters, said plug having a plurality of spaced portions thereon ofgreater diameter than the diameter of one of said ferrule meansportions, said plug portions overlapping said one of said ferrule meansportions in one rotative position of said plug confining said ferrulemeans for a limited sliding movement between said plug portions, one ofsaid plug portions comprising an elongated partially arcuate memberhaving a diameter along its major axis greater than and a width alongits minor axis less than the said one ferrule means portion diameter,rotation of said plug to another position withdrawing said one of saidplug portions from overlapping said one of said ferrule means portionspermitting separation of said can and plug.

References Cited in the file of this patent UNITED STATES PATENTS960,091 Holden May 31, 1910 2,563,744 Price Aug. 7, 1951 2,692,478 Hilll Oct. 26, 1954 FOREIGN PATENTS 587,564 Great Britain Apr. 30, 1947670,092 Great Britain Apr. 16, 1952

1. IN COMBINATION IN A TURBOMACHINE, A CASING DEFINING A COMBUSTIONCHAMBER, A COMBUSTION CAN IN SAID CHAMBER FOR THE BURNING OF FUELTHEREIN, SAID CASE AND CAN EACH HAVING A OPENING THEREIN FOR RECEIVINGTHERETHROUGH OPPOSITE ENDS OF A FUEL IGNITER PLUG, A FUEL IGNITER PLUGINSERTABLE THROUGH SAID OPENINGS AND ROTATABLE TO A PLURALITY OFPOSITIONS, MEANS REMOVABLY SECURING ONE END OF SAID PLUG TO SAID CASING,AND OTHER MEANS SLIDABLY MOUNTING SAID CAN ON SAID PLUG, SAID OTHERMEANS INCLUDING FERRULE MEANS SECURED TO SAID CAN RECEIVE SAID IGNITERPLUG THERETHROUGH IN THE ASSEMBLED POSITIONS OF SAID PLUG AND CAN, SAIDFERRULE MEANS HAVING PORTIONS OF DIFFERENT INTERNAL DIAMETERS, SAID PLUGHAVING A PLURALITY OF SPACED PORTIONS THEREON OF GREATER DIAMETER THANTHE DIAMETER OF ONE OF SAID FERRULE MEANS PORTIONS, SAID PLUG PORTIONSOVERLAPPING SAID ONE OF SAID FERRULE MEANS PORTIONS IN ONE ROTATIVEPOSITION OF SAID PLUG CONFINING SAID FERRULE MEANS FOR A LIMITED SLIDINGMOVEMENT BETWEEN SAID PLUG PORTIONS.